sim = plensa.Plensa;
sim.species('gene',1);
sim.species('mrna',0);
sim.species('protein',0);
sim.reaction('gene => gene + mrna',10.0);
sim.reaction('mrna => *',1.0);
sim.reaction('mrna => mrna + protein',10.0);
sim.reaction('protein => *','if (protein <= 100) rate = 0.0; else rate = 1e9;');
result = zeros(101,4);
for i=1:101
  result(i,1) = sim.time();  
  result(i,2) = sim.population('gene');  
  result(i,3) = sim.population('mrna');  
  result(i,4) = sim.population('protein');
  sim.simulate(1.0);
end
result;
